This invention relates to a device for cooling a superconductive high-frequency resonator with a liquid coolant and further relates to a method of making such a cooling device.
Superconductive resonators are used, for example, for accelerating and deflecting particles. They are advantageous since they operate with significant energy saving. For setting and maintaining the superconductive state, the superconductive structures have to be cooled continuously with a coolant such as liquid helium.
The cooling of high-frequency resonators is known and is achieved either by submerging the superconductive resonator into a bath of liquid helium which is at a temperature of 4.2 K or the resonator vessel is of a dual-wall (jacket) structure filled with liquid helium which is continuously circulated and replaced.
The above-outlined arrangements have a number of disadvantages. Thus, particularly in the immersion process, the resonator vessel, in the inside of which a high vacuum of less than 10.sup.-8 Torr is to be maintained, is exposed to the pressure fluctuations of the helium bath which cause deformations of the resonator and thus lead to undesirable changes in the resonant frequency. Further, a leakage of liquid helium into the resonator can be prevented only by particular structural arrangements for increasing the sealing effect. Although these disadvantages may be, to a large measure, avoided by using a dual-wall resonator, this latter solution is structurally complex and thus leads to high costs.